PPRuNe Forums - Practical Hydroplanning Advice

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Does not checking the pressure release the nitrogen and lower the pressure?

Not to any significant measure, probably more licks in a tootsy pop to get to the center than checking tire pressure to lower it more than 1 psi.

:confused::confused::confused:
so 1500' feet require use of the semicircular rule; I can fly VFR at FL180?
and
no one noticed that I wrote E instead of L for the WCA?

and

that's why pilots don't fiddle with high pressure tires:rolleyes:

VFR cruising alt. is at 3000'. Below 3000' it is no longer called VFR cruising altitude, so my answer is still correct.:suspect:

Quote:

Not to any significant measure, probably more licks in a tootsy pop to get to the center than checking tire pressure to lower it more than 1 psi.

Nitrogen gas, a group 15 element, with a valence shell rangin from 1-5; being a relatively inert gas due to its electron configuration and readiness to form double bonds. It still will expand and contract due to temperature, and even with a 1 psi reduction in pressure, there will be some significant less potential for pressure going over the limits.
Nowadays some aircraft are equipped with sensing systems in each tire that can relieve tire pressure as needed due to changing temperature conditions.

Quote:

I can fly VFR at FL180?

No, as it is class A controlled airspace. It is IFR for FL180 to FL 600 (18000'-60000') Jet routes are included in class A airspace.

However, if you lose all two way radio communications in VFR clearance.
Read the AIM:

Quote:

6-4-1. Two-way Radio Communications Failure

... 2. VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable.
NOTE- This procedure also applies when two-way radio failure occurs while operating in Class A airspace. The primary objective of this provision in 14 CFR Section 91.185 is to preclude extended IFR operation by these aircraft within the ATC system. Pilots should recognize that operation under these conditions may unnecessarily as well as adversely affect other users of the airspace, since ATC may be required to reroute or delay other users in order to protect the failure aircraft. However, it is not intended that the requirement to land as soon as practicable" be construed to mean "as soon as possible. Pilots retain the prerogative of exercising their best judgment and are not required to land at an unauthorized airport, at an airport unsuitable for the type of aircraft flown, or to land only minutes short of their intended destination.

FAR 91.185

Quote:

91.185 IFR operations: Two-way radio communications failure.
(a) General. Unless otherwise authorized by ATC, each pilot who has two-way radio communications failure when operating under IFR shall comply with the rules of this section.
(b) VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable.

FAR 91.59

Quote:

Sec. 91.159 VFR cruising altitude or flight level.

Except while holding in a holding pattern of 2 minutes or less, or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC: (a) When operating below 18,000 feet MSL and—
(1) On a magnetic course of zero degrees through 179 degrees, any odd thousand foot MSL altitude +500 feet (such as 3,500, 5,500, or 7,500); or
(2) On a magnetic course of 180 degrees through 359 degrees, any even thousand foot MSL altitude +500 feet (such as 4,500, 6,500, or 8,500).
(b) When operating above 18,000 feet MSL to flight level 290 (inclusive) and—
(1) On a magnetic course of zero degrees through 179 degrees, any odd flight level +500 feet (such as 195, 215, or 235); or
(2) On a magnetic course of 180 degrees through 359 degrees, any even flight level +500 feet (such as 185, 205, or 225).
(c) When operating above flight level 290 and—
(1) On a magnetic course of zero degrees through 179 degrees, any flight level, at 4,000-foot intervals, beginning at and including flight level 300 (such as flight level 300, 340, or 380); or
(2) On a magnetic course of 180 degrees through 359 degrees, any flight level, at 4,000-foot intervals, beginning at and including flight level 320 (such as flight level 320, 360, or 400).

So, yes under zero radio communication you may fly VFR in FL180. VFR cruising altitude is 3000' or better except under brief circumstances.

You Are Mistaken; Please Read...Agaricus

Quote:

A Hydroplane is a kind of speedboat. Did you by any chance mean to ask about "Aquaplaning"????

Hydroplane - Wikipedia, the free encyclopedia

Never mind. Accuracy has never been seen as particurlarly important on PPRuNe.

No!!! And wikipedia is not a legitimate resource anyways. Hydoplaning does refer to a speedboat at the surface of water; water has higher surface tension due to its hydrogen bonds and air water surface interface. The official term used for the "aquaplaning" of tires with water on a run way is also called hydroplaning. There are 3 types of hydoplaning which are as follows: dynamic, viscous and reverted rubber. Dynamic hydroplaning requires 0.1 of an inch or more of standing water onm the runway. Any of the following can worsen the hydroplaning issue: excessive tire wear tread, lack of depth groove, and tire, overinflation. In the airplane itself it feels like sliding and jerking, usually from side to side.
Viscous hydoplaning is believed to be the most common of the three types of hydroplaning. Viscous hydroplaning occurs on smooth runways or ones where there are rubber deposits, like in the touch down area.
Reverted rubber hydpoplaning require a wet runway and a skid in progress. This is due to brake lock and the heat produced by friction. In physics this is termed a form of balancing force. The heat is energy in transit due to temperature difference produced by the excitation of molecules by the force of friction.
The formula to determine the speed of an aircraft when hydroplaning is 8.6* the square root of the tire pressure measured in IB/in^2 (pounds per square inch) This equation gives you the lowest entry speed. However, the nosewheel and the main gear will begin hydroplaning at a different speed in knots. The best way to avoid hydoplaning is to touch down below the minimum recommended touchdown speeds if there is water on the runway. Once hydroplaning begins, it can continue below the minimum hydroplaning speeds.

Pilot's Encyclopedia of Aeronautical Knowledge is your friend:ok: while wikipedia is not:eek:...
Contaminated tires can be an often overlooked, but important issue.

3mm of water. Below that figure the runway is wet. Deeper water means it's contaminated. Greater than 13mm er something else terrible happens.

If you call finals and tower tell you recent rain, wet with water patches would it be so bad to loitter for a few more mins until wet appears on the ATIS?

Sir George Cayley

3.0mm= O.118 inches with three digits, or about 0.12 inches... 2 significant digits, which is 'around' 0.10 inches.

I guess I should not ask questions from the Advanced British PPL:rolleyes:

for that example above my compass correction card says for hdg 090 fly 085 [radio on]

what hdg do I fly on the DG? so that my course and track are coincident?

PA

Why are you posting answers to compass issues on a thread started about hydroplaning?

Just curious - as you where.

SGC

Sir George Cayley; it's because, I'm lost:}

Some historical stuff

The formula for hydroplanning speed [and the effects of slush on acceleration] was derived from a Convair 880 and a Boeing 707 from trials conducted in Florida's NASA Dryden research center conducted in August 1961

[how'd they get slush in August in Florida---I have no clue:confused:]

note there's no formula for slush effects but the syntax implies that I meant so; I meant the trials also studied the effects of slush were conducted,...:)

PA

Probably useful to review some of the work on this stuff ...

(a) Derivation of an empirical equation relating critical hydroplaning speed .... NASA

(b) Continued Research on Tire Hydroplaning .. NASA

(c) Phenomena of pneumatic tire hydroplaning

(d) this article has a picture of a sled test facility and there are some video runs in this PR video from NASA.

(e) The other technique is to pond a narrow section of runway and run the tests on a single wheel assembly, typically the nose wheel. This, as I recall from seeing some footage years ago was the basis for the tests in the early 60s .. but I haven't been able to track down any video records. The technique is used also for engine water ingestion qualification trials. For info, this Airbus video gives you an idea of the technique.

(f) Spindown research clip

There's plenty of other stuff around if you want to do some searches ...

(Checkboard cited (c) but it's such a basic report on the subject it's worth repeating here.)

Quote:

Amazing the new class of "intellectuals" we are getting out there who think an entry in a free encyclopedia, written by anyone who feels like it, is a supporting argument.

I wouldn't argue the point that quoting a freely editable encyclopedia to back an argument is pretty dubious...

But, to be fair to Wikipedia, the article quoted has immediately under the title:
"This article is about a specific type of motorboat. For other uses, see Hydroplaning."

:)